<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>单列布局</title>
	<link rel="stylesheet" href="单列布局.css">
</head>
<body>
	<div class="parent">
		哈哈哈
		<div class="child">
			弟弟救我丶
		</div>
	</div>
</body>
</html>